Optically active pyridineethanol derivatives are compounds useful as starting materials and intermediates of the synthesis of medicinals, agrochemicals and the like, which are required to be optically active.
As for the production of an optically active monocyclic pyridineethanol derivative, a method is known which comprises converting an acetylpyridine to the simplest optically active pyridineethanol derivative, namely hydroxyethylpyridine, using baker's yeast or like microorganisms (Japanese Kokai Publication Sho-61-22791), for instance.
As for the production of an optically active polycyclic pyridineethanol derivative, some methods are known: the method comprising effecting optical resolution of racemic 5-(1-hydroxyethyl)furo[2,3-c]pyridine or 5-(1-hydroxyethyl)-3-methylfuro[2,3-c]pyridine through asymmetric esterification using lipase type 2 from swine pancreatic (WO 9635678), and the method comprising effecting optical resolution of racemic 7-chloro-5-(1-hydroxyethyl)furo[2,3-c]pyridine through asymmetric esterification using Candida antarctica lipase (Synlett, 41, (1999)), for instance. However, these methods are based on optical resolution, hence the yield of one enantiomer is at most 50%, which is low and unsatisfactory.
Further, a method is known which comprises chemically reducing 5-(1-acetyl)-7-chloro-3-methylfuro[2,3-c]pyridine with (−)-chlorodiisopinocampheylborane in tetrahydrofuran to thereby obtain (S)-7-chloro-5-(1-hydroxyethyl)-3-methylfuro[2,3-c]pyridine (Journal of Organic Chemistry, 63, 7851 (1998)). Since, however, the expensive reducing agent is used in large amounts, it is difficult to put the method into practical use.